Furnace for the electrothermic production of carbon disulfide



E. HALM ET AL 2,684,393 FURNACE FOR THE ELECTROTHERMIC PRODUCTION OF CARBON DISULFIDE Filed Aug. 10, 1949 July 20, 1954 IN VENTORS RD HALM, SALADIN w ELM vow EDUA OT Fl6.l

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DER BEY 7 MA /74% ATTORNEYS Patented July 20, 1954 FURNACE FOR THE ELECTROTHERMIC PRODUCTION OF CARBON DISULFIDE Eduard Halm, IOtto Saladin, and Wilhelm von dcr Bey, Schweizerhalle, Basel-Land; Switzerland, assignors to Saeurefabrik Schweizerhall, Schweizerhalle,Basel-Land, Switzerland, azcorporate body of Switzerland Application August 10, 1949, Serial No. 109,438

Claims priority, application Switzerland June 11, 1949 13 Claims. 1

This invention relates to certain improvements in: or relating to a furnacefor the electrcthermic production of carbon disulphide.

The furnace herein disclosed is provided for the direct electric heating of loose material to which the current is supplied by two electrodes arranged in superposition, said electrodes having direct contact with the loose material serving as a resistor. The furnace is characterized in that in the top of the shaft the electric current is supplied to the loose material in frame-shaped distribution at a definite minimum horizontal distance from the circumference of the loose material underneath, said distance being determined on the one hand by the temperature desired in the interior of the loose material and on the other by the permissible temperature of its peripheral zone.

The special object of the present invention is to provide a process and. a furnace for the electrothermic production of carbon disulphide by introducing sulphur in condensed form. Various processes and types of furnaces for this purpose are already known.

In one case of av known type of furnace a plurality of rod-shaped carbon electrodes are introduced from the top and from the sides and dip into a pot-like furnace filled with charcoal, the coal being heated by a horizontal path of current. bath of liquid sulphur which vaporizes at its surface, rises through the glowing layer of charcoal and reacts with it to form carbon disulphide. Above the central portion of the pot there is a high shaft filled with charcoal through which the reaction gases escape for the purpose of giving up their heat contents. The electrodes attain a very high local temperature and thus participate themselves in the reaction which results in a remarkable great wearing away of the same. Moreover the output of the furnace is ver low in proportion to its dimensions.

In another known shaft type furnace filled with charcoal, a graphite block underneath the column of material serves as a bottom electrode and a centrally or laterally arranged graphite rod in the uppermost part of the column of material as a top electrode. The sulphur is introduced in liquid form, somewhat above the bottom electrode, into the charcoal column and vaporizes on its way down before reaching, the bottom electrode. In order to generate locally the temperature necessary for its vaporization the charcoal column is contracted immediately above the bottom electrode by a reduction in area In the bottom of the furnace there is a of the free shaft cross section. This latter measure, however, results in the furnace material being subjected to extremely severe service conditions, particularly in the event of locating the upper electrode laterally in the furnace. Of course, also, the wearing away of the electrodes is very great.

In still another known construction of a shaft furnace filled with charcoal, a water cooled metallic bottom electrode is used, above which the liquid sulphur is vaporized. A graphite rod arranged in the perpendicular axis of the furnace which is partly protected by a bricked-up cylinder serves as the upper electrode. An intermediate space between protective cylinder and graphite rod is filled with carbon in pieces. In addition to that liquid sulphur is caused to flow down through this intermediate space to cool the electrode.

All the furnace types with rod-shaped upper electrodes have the disadvantage that the current introducing cross section of the electrode is very small compared with the shaft cross section so that the current flows only through a relatively small portion of. the loose material which is. the reason, why all of'such furnace types have a low output. Moreover, charging of the material around the rod-shaped electrode is greatly hampered and non-uniform. Another diniculty consists in providing a tight packing for the electrodes which, owing to their consumption, have to be frequently replaced.

The drawbacks-mentioned above are eliminated in the process according to the present invention. It has been found that it is possible during direct electric heating of the loose material, without. substantially altering the manner in which the current is passing through. the loose material, to cause the vaporization of non-conducting liquid substances or of substances becoming liquid under the conditions of the process, particularly liquid sulphur, within the loose materialand to'further heat the vapor in the upper zone of the loose material'and to effect a reaction of the same with the said loose material. Thus theprocess for the production of carbon disulphide according to the present invention consists in that the electric current is supplied to the filled incarbonaceous material by the upper electrode in frame-shaped distribution and at a definite minimum: horizontal distance from the periphery of the carbonaceous material underneath and that the sulphur introduced continuously according to'thedemand is vaporized from a bath located above the lower electrode at the foot of the coal column. The said minimum distance is determined on the one hand by the reaction temperature required in the interior of the loose material and on the other by the permissible temperature of the peripheral zone of said material,

which must not be exceeded particularly with regard to the material of the inside wall of the furnace. The electric current is advantageously supplied to the coal also through the lower electrode at a definite minimum horizontal distance from the circumference of the carbonaceous material located above in order to assist the effect described above. In selecting the said distance there are still to be considered the electric conductivity of the carbonaceous material, its temperature characteristics and the thermal conductivity of the coal.

The annular introduction of the current by the upper electrode, which is effected onto a comparatively large cross section, permits a considerably better distribution of the current within the loose carbonaceous material and thereby a more uniform heating of the same so that the process in question, compared with the volume of the carbonaceous material employed, produces considerably more carbon disulphide than was possible in the application of processes and furnace types known hitherto. Notwithstanding the fact that there is only a very slight attack of the sulphur on the furnace wall, as the sulphur also has a lower temperature in the peripheral zone than in the interior of the loose material, for, as already mentioned, only a small part of the current flows through the peripheral zone of the coal, the influence of the vaporizing liquid sulphur at the lower electrode on the flow of the current is only insignificant.

A shaft furnace particularly suitable for carry ing into practice the process of this invention is characterized by a frame-shaped upper electrode, the circumference of the downward facing, current introducing surface having a definite minimum horizontal distance from the inside wall of the reaction shaft therebeneath, and is characterized by a lower electrode covered with liquid sulphur and carbonaceous material. The said minimum distance is determined, apart from the temperature required in the interior of the column of carbonaceous material, also by the corrosion resistance and refractoriness of the furnace wall. It is an advantage to arrange also the periphery of the current introducing surface of the lower electrode at a definite minimum horizontal distance from the inside wall of the reaction shaft located above.

The upper as well as the lower electrode may have the shape of a closed frame or each may consist of homcpolar parts (i. e. the parts of the electrode all have the same electrical potential) arranged, considered as a whole, in the shape of a frame and may be round, oval or polygonal and are referred to herein as frame-shaped electrodes. The electrodes may be supported upon a suitable structure, preferably a contraction in area of the shaft, or on brackets protruding from the wall of the same. They may also be secured to rods which, if desired, may be in the form of cooled tubes etc. The lower electrode, which is covered with sulphur, may advantageously be arranged lying on the furnace bottom and have the shape of a plate. The electrodes and the current leads may advantageously be designed as hollow bodies through which, for the purpose of cooling, a heat eliminating medium may be conducted.

The electrodes advantageously consist of metals, e. g. iron or alloys of iron. They may also be covered with a current conductive protective coating, e. g. with Soderberg type nonmetallic electrode mass consisting of an adherent mass derived from broken loose graphite and pitch.

The process according to the invention will be further explained with reference to advantageous furnace designs shown by way of example in the accompanying drawings, in which:

Fig.1 is a vertical section through a preferred embodiment of such type of furnace;

Fig. 2 is a horizontal cross-sectional view of a furnace at the level of the upper electrode;

Fig. 3 is a vertical cross-sectional view of the upper part of a furnace with an upper electrode in the form Of a pipe coil; and

Fig. 4 is a plan view of a bottom electrode for a furnace.

The furnace according to Fig. 1 comprises a bricked-up shaft l with a sheet shell la and is provided with a chute 2 having a closure 2a for the carbonaceous material, a gas outlet pipe connection 3 and a discharge pipe The upper electrode 5 consists of a water cooled pipe coil 5a covered with Siiderberg electrode mass 5b supported on a contraction lb of the area of the shaft. The lower electrode 5 is designed as an iron plate lying in the bottom of the furnace. The whole shaft is filled with carbonaceous material, e. g. with charcoal. The electric current is introduced by the leads I and 8. At 8 liquid sulphur is introduced which forms a sump iii. From this sump the sulphur is vaporized and rises as vapor through the glowing carbonaceous material, thereby reacting with the same. The major part of the current flows within a cross section, the periphery of which is at a horizontal distance i i from the inside wall of the shaft consisting of fireclay bricks. The diameter of the shaft is about 5 ft., the height between the electrodes about 11 /2 ft. and their minimum horizontal distance from the wall of the shaft about 14: in. The

carbonaceous material is heated to about 1850 F., the inside wall of the shaft below the upper electrode presenting an internal tempereature of only 1100 F. The current intensity taken up by the furnace e. g. at a voltage of about volts is about 1500 amp. and the production amounts to 11,500 lb. of carbon disulphide every 24 hours.

As shown in Fig. 2, the electrode consists of three homopolar parts connected with the same pole of the electrical current supply supported on brackets 50. The parts consist of hollow bodies 5a through which water may be conducted. The flanges 5d at each end of these bodies serve for feeding and draining of the water and simultaneously also for the connection with the electrical power. The electrodes are protected by Soderberg electrode mass 513, i. e. a calcined mixture composed of coarse graphite and pitch.

In Fig. 3'the upper part of a furnace is shown provided with an upper electrode 5 in the form of a pipe coil carried by tubes 5d which also serve for feeding and draining of a cooling liquid as well as for introducing the electrical current.

In Fig. 4 is shown a bottom electrode for a furnace of the type identified consisting of a plate ta having an internal passageway 6b for circulating a fluid cooling means which enters and leaves the plate through pipes 60 and Kid.

The process according to the invention may, however, be conducted also with furnace types of similar design inasmuch as the same have the characteristic features described above. Instead of using charcoal in the process it is also possible to employ other suitable materials, advantageously non-gassing carbonaceous material with a low percentage of ash such as e. g. petroleum coke, anthracite coal or coke, in which case voltage and amperage should be adapted to the material.

This application is a continuation-in-part of our application Serial Number 109,392, filed August 9, 1949, now abandoned, corresponding to Swiss application Number 45,155, filed May 20, 1949, now Swiss Patent Number 278,580, allowed October 31, 1951, and published February 1, 1952.

We claim:

1. In a shaft furnace for the electrothermic production of carbon compounds from loose, solid non-volatile carbonaceous material and volatile reagents by the passage of current between two vertically spaced electrodes through the car b-onaceous material therebetween, the combination comprising a vertical shaft within said furnace the inside walls of which consist of a refractory, electrically insulating material, said Vertical shaft being filled with a bed of said solid carbonaceous material forming the electrical conductor between said electrodes, a frameshaped first electrode located in the upper section of said vertical shaft and being provided with passageways therethrough adapted for circulating fluid cooling means, said first electrode having its downwardly facing current introducing surface positioned within said furnace with said surface spaced horizontally inward relative to the inside walls of said vertical shaft below said electrode, and a second electrode located in the lower section of said vertical shaft at a distance from said first electrode substantially exceeding the diameter of said vertical shaft, said inside walls of said shaft between the upper and lower electrodes being in contact with said bed of solid material.

2. In a shaft furnace for the electrothermic production of carbon compounds from loose, solid non-volatile carbonaceous material and volatile reagents by the passage of current between two vertically spaced electrodes through the carbonaceous material therebetween, the combination comprising a vertical shaft within said furnace the inside walls of which consist of a refractory, electrically insulating material, said vertical shaft being filled with a bed of said solid carbonaceous material contacting and forming the electrical conductor between said electrodes, a frameshaped first electrode located in the upper section of said vertical shaft and being provided with passageways therethrough adapted for circulating fiuid cooling means, said first electrode having a downwardly facing current introducing surface positioned within said furnace with the inner and outer periphery of said surface being spaced horizontally inward relative to the inside vertical walls of said vertical shaft below said electrode, and a second electrode located in the lower section of said vertical shaft at a distance from said frame-shaped electrode substantially exceeding the diameter of said vertical shaft and having its periphery spaced horizontally inward relative to the inside walls of said vertical shaft, said inside walls of said shaft between the upper and lower electrodes being in contact with said bed of solid material.

3. In a shaft furnace for the electrothermic production of carbon compounds from loose, solid non-volatile carbonaceous material and volatile reagents by the passage of current between two vertically spaced electrodes through the carbonaceous material therebetween, the combination comprising a vertical shaft within said furnace the inside walls of which consist of a refractory, electrically insulating material, said vertical shaft being filled with a bed of said solid carbonaceous material forming the electrical conductor between said electrodes, an annular first electrode located in the upper section of said vertical shaft and being provided with passageways therethrough adapted for circulating fluid cooling means, said annular electrode having its downwardly facing current introducing surface positioned within said furnace with the inner and outer periphery of said surface spaced horizontally inward relative to the inside vertical walls of said vertical shaft below said electrode, and a plate-shaped second electrode located in the lower section of said vertical shaft at a distance from said first electrode substantially exceeding the diameter of said vertical shaft and having its periphery spaced horizontally inward from the inside walls thereof, said inside walls of said shaft between the upper and lower electrodes being in contact with said bed of solid material.

4. In a shaft furnace for the electrothermic production of carbon compounds from loose, solid non-volatile carbonaceous material and volatile reagents by the passage of current between two vertically spaced electrodes through the carbonaceous material therebetween, the combination comprising a vertical shaft within said furnace the inside walls of which consist of a refractory, electrically insulating material, said vertical shaft being filled with a bed of said solid carbonaceous material forming the electrical conductor between said electrodes, a frame-shaped first electrode located in the upper section. of said vertical shaft and being provided with passageways therethrough adapted for circulating fiuid cooling means, said first electrode having its downwardly facing current introducing surface positioned within said furnace with said surface spaced horizontally inward relative to the inside walls of said vertical shaft below said electrode, and a second electrode located in the lower section of said vertical shaft at a distance from said first electrode substantially exceeding the diameter of said vertical shaft and having its periphery spaced horizontally inward relative to the inside walls of said vertical shaft, said inside walls of said shaft between the upper and lower electrodes being in contact with said bed of. solid material, at least one of said electrodes being supported upon a restricted area within said furnace.

5. In a shaft furnace for the electrothermic production of carbon compounds from loose, solid non-volatile carbonaceous material and volatile reagents by the passage of current between two vertically spaced electrodes through the carbonaceous material therebetween, the combination comprising a vertical shaft within said furnace the inside walls of which consist of a refractory, electrically insulating material, said vertical shaft being filled with abed of said solid carbonaceous material contacting and forming the electrical conductor between said electrodes, a frame-shaped first electrode located in the upper section of said vertical shaft and being provided with passageways therethrough adapted for circulating fluid cooling means, said first electrode having its downwardly facing current in troducing frame-shaped surface positioned within said furnace with the inner and outer periphery of said surface spaced horizontally inward relative to the inside vertical walls of said vertical shaft below said electrode, and a second electrode located in the lower section of said vertical shaft at a distance from said first electrode substantially exceeding the diameter of said vertical shaft and having its periphery spaced horizontally inward relative to the inside walls of said vertical shaft, the inside walls of said shaft between the upper and lower electrodes being incontact with said bed of solid material, at least one of said electrodes being supported upon brackets constructed in said shaft.

6. In a shaft furnace of the electrothermic production of carbon compounds from loose, solid non-volatile carbonaceous material and volatile reagents by the passage of current between two vertically spaced electrodes through the carbonaceous material therebetween, the combination comprising a vertical shaft within said furnace the inside walls of which consist of a refractory, electrically insulating material, said vertical shaft being filled with a bed of said solid carbonaceous material forming the electrical conductor between said electrodes, 2. frameshaped first electrode located in the upper section of said vertical shaft and being provided with passageways therethrough adapted for circulating fluid cooling means, said first electrode having its downwardly facing current introducing surface positioned within said furnace with said surface spaced horizontally inward relative to the inside walls of said vertical shaft below said electrode, and a second electrode located in the lower section of said vertical shaft at a distance from said first electrode substantially exceeding the diameter of said vertical shaft and havin its periphery spaced horizontally inward relative to the inside walls of said vertical shaft and being provided with passageways therethrough adapted for circulating fluid cooling means, said inside walls of said shaft between the upper and lower electrodes being in contact with said bed of solid material.

'7. In a shaft furnace for the electrothermic production of carbon compounds from loose, solid non-volatile carbonaceous material and volatile reagents by the passage of current between two vertically spaced electrodes through the car bonaceous material therebetween, the combination comprising a vertical shaft within said furnace the inside walls of which consist of a refractory, electrically insulating material, said vertical shaft being filled with a bed of said solid carbonaceous material forming the electrical conductor between said electrodes, a frame-shaped first electrode located in the upper section of said vertical shaft and being provided with passageways therethrough adapted for circulating fluid cooling means, said first electrode having a downwardly facing current introducing surface positioned within said furnace with the inner periphery of said surface being spaced horizontally inward relative tothe inside walls of said vertical shaft below said electrode, and a second electrode located in the lower section of said vertical shaft having its periphery spaced horizontally inward relative to the inside walls of said shaft and positioned on the bottom thereof at a distance from said first electrode substantially exceeding the diameter of said vertical shaft, the inside walls of said shaft between the upper and lower electrodes being in contact with said bed of solid material.

8. In a shaft furnace for the electrothermic production of carbon compounds from loose, solid non-volatile carbonaceous material and volatile reagents by the passage of current between two vertically spaced electrodes through the carbonaceous material therebetween, the combination comprising a vertical shaft within said furnace the inside walls of which consist of a refractory, electrically insulating material, said vertical shaft being filled with a bed of said solid carbonaceous material forming the electrical conductor between said electrodes, a frameshaped first electrode located in the upper section of said vertical shaft and being provided with passageways therethrough adapted for circulating fluid cooling means, said first electrode having a downwardly facing current introducing surface positioned within said furnace with the inner and outer periphery of said surface spaced horizontally inward relative to the inside vertical walls of said vertical shaft below said electrode, and a second electrode located in the lower section of said vertical shaft at a distance from said first electrode substantially exceeding the diameter of said vertical shaft and having its periphery spaced horizontally inward relative to the inside walls of said vertical shaft, the inside Walls of said shaft between the upper and lower electrodes being in contact with said bed of solid material, at least one of said electrodes consisting of a metal covered with current conducting non-metallic coating.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 614,930 Burton Nov. 29, 1898 630,966 Bohm Aug. 15, 1899 662,537 Koller Nov. 27, 1900 702,117 Taylor June 10, 1902 1,056,045 Murray Mar. 18, 1913 1,177,680 Brown Apr. 4, 1916 1,315,992 Sejournet Sept. 16, 1919 1,544,151 Helfenstein June 30, 1925 1,549,812 Siedler Aug. 18, 1925 1,634,478 Wickenden et al. July 5, 1927 1,680,630 Okell Aug. 14, 1928 

1. IN A SHAFT FURNACE FOR THE ELECTROTHERMIC PRODUCTION OF CARBON COMPOUNDS FROM LOOSE, SOLID NON-VOLATILE CARBONACEOUS MATERIAL AND VOLATILE REAGENTS BY THE PASSAGE OF CURRENT BETWEEN TWO VERTICALLY SPACED ELECTRODES THROUGH THE CARBONACEOUS MATERIAL THEREBETWEEN, THE COMBINATION COMPRISING A VERTICAL SHAFT WITHIN SAID FURNACE THE INSIDE WALLS OF WHICH CONSIST OF A REFRACTORY, ELECTRICALLY INSULATING MATERIAL, SAID VERTICAL SHAFT BEING FILLED WITH A BED OF SAID SOLID CARBONACEOUS MATERIAL FORMING THE ELECTRICAL CONDUCTOR BETWEEN SAID ELECTRODES, A FRAME SHAPED FIRST ELECTRODE LOCATED IN THE UPPER SECTION OF SAID VERTICAL SHAFT AND BEING PROVIDED 